Bicycle crank axle assembly

ABSTRACT

A bicycle crank axle assembly has first and second crank arms that are attached to opposite ends of a crank axle. The ends of the crank axle are non-rotatably disposed in axle mounting openings of the first and second crank arms. A first end of the crank axle has at least one axially extending first spline that protrudes radially outward from an outer peripheral surface of its middle body portion. The at least one axially extending first spline non-rotatably couples the crank axle to the first crank arm and prevents outward axial movement of the first crank arm away from the second crank arm. The second end portion of the crank axle has at least one recess that extend radially inward with respect to the outer peripheral surface of the middle body portion to form at least one axially extending second spline.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/304,336 filed on Nov. 24, 2011. The entire disclosure ofU.S. patent application Ser. No. 13/304,336 is hereby incorporatedherein by reference.

BACKGROUND

1. Field of the Invention

This invention generally relates to a bicycle crank axle assembly. Morespecifically, the present invention relates to a bicycle crank axleassembly having an attachment structure between a pair of crank arms anda crank axle.

2. Background Information

Generally speaking, a conventional bicycle has a diamond-shaped bicycleframe with a pair of wheels rotatably mounted to the frame and a drivetrain coupled to the frame for driving the rear wheel. The drive traintypically has a bicycle crank assembly mounted to the cylindrical ortubular hanger part of the bicycle frame. The bicycle crank assemblydrives a chain that rotates a sprocket mounted to the rear wheel. Thebicycle crank assembly usually includes a crank axle that is mounted ina freely rotatable-manner to a hanger tube of the bicycle frame. A crankarm is fastened to each end of the crank axle. The right crank armtypically has one or more sprockets attached thereto for driving thechain. As used herein, the terms “right” and “left” are often used todescribe bicycle components on the assumption that the bicycle is viewedfrom the rear.

SUMMARY

One aspect presented in this disclosure is to provide a bicycle crankassembly that is relatively easy to assemble.

In view of the state of the known technology, a bicycle crank assemblyis presented in this disclosure that comprises a first crank arm, asecond crank arm and a crank axle. The first crank arm includes a firstaxle mounting opening that is through bore. The second crank armincludes a second axle mounting opening. The crank axle includes a firstend portion, a second end portion and a middle body portion locatedbetween the first and second end portions, the crank axle being mountedin the first axle mounting opening of the first crank arm with anon-interference fit therebetween, and the first end portion of thecrank axle is attached to the first axle mounting opening by adhesive.The first end portion of the crank axle has at least one axiallyextending first spline that protrudes radially outward from an outerperipheral surface of the middle body portion, the first end portion ofthe crank axle being disposed in the first axle mounting opening, the atleast one axially extending first spline non-rotatably coupling thecrank axle to the first crank arm and preventing outward axial movementof the first crank arm away from the second crank arm along the crankaxle, the second end portion of the crank axle having at least onerecess that extend radially inward with respect to the outer peripheralsurface of the middle body portion to form at least one axiallyextending second spline, the second end portion of the crank axle beingnon-rotatably disposed in the second axle mounting opening.

These and other objects, features, aspects and advantages of the bicyclecrank assembly presented in this disclosure will become apparent tothose skilled in the art from the following detailed description, which,taken in conjunction with the annexed drawings, discloses severalembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is an assembled perspective view of a bicycle crank assembly inaccordance with a first embodiment;

FIG. 2 is an exploded perspective view of the bicycle crank assemblyillustrated in FIG. 1;

FIG. 3 is a transverse cross sectional view of the bicycle crankassembly illustrated in FIGS. 1 and 2 with the cross section taken alongthe center longitudinal axis of the crank axle and generally bisectingthe crank arms in the lengthwise direction;

FIG. 4 is an enlarged partial cross sectional view of selected portionsof the bicycle crank assembly illustrated in FIGS. 1 to 3;

FIG. 5 is an enlarged partial cross sectional view of the crank axleattachment portion of the left bicycle crank arm for the bicycle crankassembly illustrated in FIGS. 1 to 4;

FIG. 6 is an enlarged partial cross sectional view of the crank axleattachment portion of the right bicycle crank arm for the bicycle crankassembly illustrated in FIGS. 1 to 4;

FIG. 7 is an elevational view of the crank axle for the bicycle crankassembly illustrated in FIGS. 1 to 4;

FIG. 8 is an enlarged partial cross sectional view of a bicycle crankassembly in accordance with a second embodiment;

FIG. 9 is a partial cross sectional view of the bicycle crank assemblyas viewed along section line 9-9 of FIG. 8;

FIG. 10 is an elevational view of the crank axle for the bicycle crankassembly illustrated in FIGS. 8 and 9;

FIG. 11 is an enlarged partial cross sectional view of a bicycle crankassembly in accordance with a third embodiment; and

FIG. 12 is an enlarged partial cross sectional view of a bicycle crankassembly in accordance with a fourth embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Selected embodiments will now be explained with reference to thedrawings. It will be apparent to those skilled in the art from thisdisclosure that the following descriptions of the embodiments areprovided for illustration only and not for the purpose of limiting theinvention as defined by the appended claims and their equivalents.

Referring to FIGS. 1 to 7, a bicycle crank axle assembly 10 isillustrated in accordance with a first embodiment. As seen in FIGS. 1 to3, the bicycle crank axle assembly 10 includes a crank axle 12, a first(right) crank arm 14 and a second (left) crank arm 16. The first crankarm 14 is fixed to a first (right) end portion of the crank axle 12,while the second crank arm 16 is fixed to a second (left) end portion ofthe crank axle 12. Basically, the first and second crank arms 14 and 16are secured to the crank axle 12 using only a fixing bolt 18. As shownin FIG. 3, the first and second crank arms 14 and 16 are fixed toopposite end portions of the crank axle 12 and extend in oppositedirections. The first crank arm 14 has a first axially outward facingsurface 14 a and a first axially inward facing surface 14 b. The secondcrank arm 16 has a second axially outward facing surface 16 a and asecond axially inward facing surface 16 b. The second crank arm 16 isremovably fastened to the crank axle 12 by the fixing bolt 18, while thefirst crank arm 14 is preferably fixed to the crank axle 12 so that thefirst crank arm 14 is integrally coupled to the crank axle 12 through asplined-connection as discussed below.

In the first illustrated embodiment, the bicycle crank axle assembly 10further includes a pair of sprockets or chainrings 20 and 22. The firstcrank arm 14 has a spider arms for attaching the sprockets 20 and 22with a plurality of fasteners (e.g., chainring nuts 24 and chainringbolts 26). The sprockets 20 and 22 are fixedly secured to the firstcrank arm 14 in a releasable and reinstallable manner. Basically, thesprockets 20 and 22 and their attachments to the first crank arm 14 areconventional and can be any suitable configuration. Moreover, the firstcrank arm 14 can be configured such that only one sprocket is attachedthereto the first crank arm 14 or more than two sprockets are attachedto the first crank arm 14. Thus, the sprockets 20 and 22 and theirattachments to the first crank arm 14 will not be discussed and/orillustrated in detail herein.

Now, the crank axle 12 will be discussed in more detail. In the firstillustrated embodiment, the crank axle 12 is a hollow pipe-shaped memberthat is highly rigid. For example, the crank axle 12 is made of ametallic material as chrome molybdenum steel. Preferably, the crank axle12 defines a longitudinal axis A that substantially coincides with arotational center axis of a bottom bracket when installed in a hangertube of a bicycle. The crank axle 12 includes a first end portion 30, asecond end portion 32 and a middle body portion 34 located between thefirst and second end portions 30 and 32. The first end portion 30 has amaximum outer dimension D1 (diameter or transverse width). The secondend portion 32 and the middle body portion 34 both have a maximum outerdimension D2 (diameter or transverse width) that is smaller than themaximum diameter D1 of the first end portion 30.

Preferably, the first end portion 30 of the crank axle 12 has aplurality of first splines 36, while the second end portion 32 of thecrank axle 12 has a plurality of second splines 38. The first and secondsplines 36 and 38 are axially extending splines that arecircumferentially spaced apart around the first and second end portions30 and 32 of the crank axle 12, respectively. Alternatively, the firstand second end portions 30 and 32 of the crank axle 12 can be providedwith fewer or more splines than illustrated (e.g., at least one axiallyextending spline at each end portion). As explained below, the firstsplines 36 non-rotatably couple the first end portion 30 of the crankaxle 12 to the first crank arm 14 and prevent outward axial movement ofthe first crank arm 14 away from the second crank arm 16 along the crankaxle 12. The second splines 38 non-rotatably couple the second endportion 32 of the crank axle 12 to the second crank arm 16.

Basically, the first splines 36 protrudes radially outward from an outerperipheral surface 40 of the middle body portion 34 to define an axiallyfacing abutment 42. The axially facing abutment 42 is formed by the endsof the first splines 36 that face towards the second end portion 32 ofthe crank axle 12. On the other hand, the second splines 38 are definedby a plurality of recesses 44 that extend radially inward with respectto the outer peripheral surface 40 of the middle body portion 34. Thus,the second splines 38 have an outermost crest that is almost flush withrespect to the outer peripheral surface 40 of the middle body portion34. Alternatively, the second splines 38 may also have an outermostcrest that is recessed with respect to the outer peripheral surface 40of the middle body portion 34. Since the recesses 44 extend radiallyinward with respect to the outer peripheral surface 40 of the middlebody portion 34, an axially facing abutment 46 is formed at the end ofeach of the recesses 44 at the middle body portion 34.

As seen in FIG. 4, the second end portion 32 of the crank axle 12 has aninternal thread 48. The fixing bolt 18 is threaded into the internalthread 48 to secure the second end portion 32 of the crank axle 12 tothe second crank arm 16. In particular, the axially facing abutments 46formed at the ends of the recesses 44 at the middle body portion 34contact the axially inside surface of the crank axle 12, while thefixing bolt 18 contacts the axially outside surface of the crank axle12. In this way, as seen in FIG. 3, the second crank arm 16 issandwiched between the fixing bolt 18 and the axially facing abutments46 of the crank axle 12.

Now, the first crank arm 14 will be discussed in more detail. The firstcrank arm 14 includes a crank body portion 50, a crank axle attachmentportion 52 and a plurality of sprocket attachment portions 54. The firstcrank arm 14 is illustrated as being formed with a two-piececonstruction from a light metal such as an aluminum alloy, a magnesiumalloy, a titanium alloy, or other suitable light metal. In particular,the crank body portion 50 has an interior space that is covered by ametallic cover member 56. The metallic cover member 56 is fixedlyattached (i.e., bonded) to a one-piece metallic body member thatincludes the crank body portion 50, the crank axle attachment portion52, the sprocket attachment portions 54. As a result, the crank bodyportion 50 has an interior space to reduce the weight of the first crankarm 14. This interior space can be empty or filled with a resin materialas needed and/or desired. However, the first crank arm 14 is not limitedto this construction. The first crank arm 14 can be formed of a singlepiece or of several pieces of various materials.

The crank body portion 50 has tip or free end portion with a pedalattachment hole 58 that is threaded for threadedly attaching a pedal(not shown) as best seen in FIG. 3. The tip or free end portion of thecrank body portion 50 constitutes a pedal attachment portion. The crankaxle attachment portion 52 has a first axle mounting opening 60 that hasa plurality of splines 62 (FIG. 6) for engaging the first splines 36 ofthe crank axle 12 to prevent rotation therebetween as seen in FIG. 4.The first axle mounting opening 60 is through bore.

The first crank arm 14 includes an axially facing abutment 64 within thefirst axle mounting opening 60. Such an axially facing abutment 64 isformed before the first crank arm 14 and the crank axle 12 are assembledwith each other. The axially facing abutment 64 is integrally formed asa unitary piece of the crank axle attachment portion 52. The axiallyfacing abutment 64 is an annular abutment. However, the axially facingabutment 64 can be a singular non-annular abutment or a plurality ofabutments as needed and/or desired. Preferably, the axially facingabutment 64 includes at least one projection extending radially inwardlyfrom an inner peripheral surface of the first axle mounting opening 60.The axially facing abutment 64 defines a minimum inner dimension of thefirst axle mounting opening 60. The second end portion 32 and the middlebody portion 34 of the crank axle 12 have the maximum outer dimension D2that is smaller than the minimum inner dimension of the first axlemounting opening 60 so that the second end portion 32 and the middlebody portion 34 of the crank axle 12 can pass through the first axlemounting opening 60. In this way, the second end portion 32 and themiddle body portion 34 of the crank axle 12 can be inserted through thefirst axle mounting opening 60 from the first axially outward facingsurface 14 a of the first crank arm 14 to the first axially inwardfacing surface 14 b of the first crank arm 14 until the axially facingabutment 42 of the crank axle 12 contacts the axially facing abutment 64of the first crank arm 14. Thus, the second end portion 32 and themiddle body portion 34 are shaped so that the second end portion 32 andthe middle body portion 34 are capable of freely passing through thefirst axle mounting opening 60 for mounting the first end portion 30 ofthe crank axle 12 in the first axle mounting opening 60 of the firstcrank arm 14.

The first end portion 30 of the crank axle 12 is dimensioned relative tothe first axle mounting opening 60 such that the first end portion 30 ofthe crank axle 12 is fixedly mounted in the first axle mounting opening60 of the first crank arm 14 with an interference fit (i.e. a press-fit)therebetween.

Now, the second crank arm 16 will be discussed in more detail. Thesecond crank arm 16 includes a crank axle attachment portion 66 and apedal attachment portion 68. The second crank arm 16 is illustrated asbeing formed with a two-piece construction from a light metal such as analuminum alloy, a magnesium alloy, a titanium alloy, or other suitablelight metal. In particular, the second crank arm 16 has an interiorspace that is covered by a metallic cover member 69. The metallic covermember 69 is fixedly attached (i.e., bonded) to the second crank arm 16.As a result, the second crank arm 16 has an interior space to reduce theweight of the second crank arm 16. This interior space can be empty orfilled with a resin material as needed and/or desired. However, thesecond crank arm 16 is not limited to this construction. The secondcrank arm 16 can be formed of a single piece or of several pieces ofvarious materials.

As best seen in FIG. 5, the second crank arm 16 includes a second axlemounting opening 70. The second axle mounting opening 70 of the secondcrank arm 16 is defined by a second inner splined surface 72. At theopposite end of the second crank arm 16, the pedal attachment portion 68has a pedal attachment hole 74 that is threaded for threadedly attachinga pedal (not shown). The second inner splined surface 72 engage thesecond splines 38 to non-rotatably couple the second end portion 32 ofthe crank axle 12 to the second crank arm 16. The axially facingabutment 46 contacts the second axially inward facing surface 16 b ofthe second crank arm 16 to prevent axially inward movement of the secondcrank arm 16 on the crank axle 12. The first and second end portions 30and 32′ are dimensioned relative to the first and second axle mountingopenings 60 and 70 such that the second end portion 32 must be insertedinto the second axle mounting opening 70 from the second axially inwardfacing surface 16 b of the second crank arm 16 toward the second axiallyoutward facing surface 16 a of the second crank arm 16 after passingthrough the first axle mounting opening 60 to dispose the first andsecond end portions 30 and 32 in the first and second axle mountingopenings 60 and 70, respectively.

The assembly of the bicycle crank axle assembly 10 will now be brieflydiscussed. The crank axle 12 is mounted the first and second crank arms14 and 16 by inserting the crank axle 12 through the first axle mountingopening 60 from the first axially outward facing surface 14 a of thefirst crank arm 14 to the axially inward facing surface 14 b of thefirst crank arm 14, preferably, until the axially facing abutment 42 ofthe crank axle 12 contacts the axially facing abutment 64 of the firstcrank arm 14, or until there is desired amount of an axial gap betweenthe axially facing abutment 42 of the crank axle 12 and the axiallyfacing abutment 64 of the first crank arm 14. In this way, the first endportion 30 of the crank axle 12 is fixedly mounted in the first axlemounting opening 60 of the first crank arm 14 with an interference fittherebetween. Also the first splines 36 engage the splines 62 of thefirst crank arm 14 to non-rotatably couple the first end portion 30 ofthe crank axle 12 to the first crank arm 14. The axially facing abutment64 of the first crank arm 14 contacts the axially facing abutment 42 ofthe crank axle 12 prevent outward axial movement of the first crank arm14 away from the second crank arm 16 along the crank axle 12.

Next, the second end portion 32 of the crank axle 12 is insert into thesecond axle mounting opening 70 from the second axially inward facingsurface 16 b of the second crank arm 16 to the second axially outwardfacing surface 16 a of the second crank arm 16, preferably, until thesecond axially facing abutment 46 contacts the second axially inwardfacing surface 16 b of the second crank arm 16, or until there isdesired amount of an axial gap between the axially facing abutment 46 ofthe crank axle 12 and the axially inward facing surface of the secondcrank arm 16. Finally, the fixing bolt 18 is threaded into the secondend portion 32 of the crank axle 12 to secure the second end portion 32of the crank axle 12 to the second crank arm 16. This, with this firstembodiment, the first and second end portions 30 and 32 are dimensionedrelative to the first and second axle mounting openings 60 and 70 suchthat the second end portion 32 must be inserted into the first axlemounting opening 60 from the first axially outward facing surface 14 aof the first crank arm 14 toward the first axially inward facing surface14 b of the first crank arm 14 to dispose the first end portion 30 inthe first axle mounting opening 60.

Referring to FIGS. 8 to 10, a bicycle crank axle assembly 110 isillustrated in accordance with a second embodiment. The bicycle crankaxle assembly 110 includes a crank axle 112, a first (right) crank arm114 and a second (left) crank arm 116. Similar to the prior embodiment,the first and second crank arms 114 and 116 are secured to the crankaxle 112 using only a fixing bolt 118. The crank axle 112 includes afirst end portion 130, a second end portion 132 and a middle bodyportion 134 located between the first and second end portions 130 and132. The bicycle crank axle assembly 110 is identical to the bicyclecrank axle assembly 10, discussed above, except that the connectionsbetween the first and second end portions 130 of the crank axle 112 tothe first and second crank arms 114 and 116 have been modified asdiscussed below. In view of the similarities between the bicycle crankaxle assembly 110 and the bicycle crank axle assembly 10, only thefeatures that are different in the bicycle crank axle assembly 110 willbe discussed herein.

Here in this second embodiment, as seen in FIG. 10, the second endportion 132 has a maximum outer dimension D3 (diameter or transversewidth) that is smaller than the maximum outer dimension D2 (diameter ortransverse width) of the middle body portion 134. Similar to the priorembodiment, the first end portion 130 of the crank axle 112 has aplurality of first splines 136, while the second end portion 132 of thecrank axle 112 has a plurality of second splines 138. The first splines136 protrude radially outward from an outer peripheral surface 140 ofthe middle body portion 134 to define an axially facing abutment 142.The second splines 138 are defined by a plurality of recesses 144 thatin the second end portion 132. Each of the second splines 138 has anoutermost crest that is recessed with respect to the outer peripheralsurface 140 of the middle body portion 134 as seen in FIG. 10. Thus, anaxially facing abutment 146 is formed at the interface between secondend portion 132 and the middle body portion 134. The second end portion132 of the crank axle 112 has an internal thread 148 for receiving thefixing bolt 118 to secure the second end portion 132 of the crank axle112 to the second crank arm 116.

The first crank arm 114 includes a crank body portion 150, a crank axleattachment portion 152 and a plurality of sprocket attachment portions(not shown). The first crank arm 114 has a first axially outward facingsurface 114 a and a first axially inward facing surface 114 b. The crankaxle attachment portion 152 has a first axle mounting opening 160(through bore) that has a plurality of splines (identical to splines 62of FIG. 6) for engaging the first splines 136 of the crank axle 112 toprevent rotation therebetween. The first crank arm 114 is identical tothe first crank arm 14, except that the crank axle attachment portion152 is provided with a recess is provided around the first axle mountingopening 160 is through bore that receives a C-shaped retaining ring 164for forming an axially facing abutment that contacts the axially facingabutment 142 of the crank axle 112. Thus, in this embodiment, theaxially facing abutment that is a separate piece attached to the crankaxle attachment portion 152. While the C-shaped retaining ring 164 isattached to the crank axle attachment portion 152 as the axially facingabutment, the axially facing abutment can have other configurations.

The second crank arm 116 includes a crank axle attachment portion 166that includes a second axle mounting opening 170. The second crank arm116 has a second axially outward facing surface 116 a and a secondaxially inward facing surface 116 b. The second crank arm 116 isidentical to the second crank arm 16, except that the size of the secondaxle mounting opening 170 has been changed to accommodate the smallersize of the second end portion 132. Thus, similar to the priorembodiment, the crank axle 112 is mounted the first and second crankarms 114 and 116 by inserting the crank axle 112 through the first axlemounting opening 160 from the first axially outward facing surface 114 aof the first crank arm 114 to the first axially inward facing surface114 b of the first crank arm 114, preferably, until the axially facingabutment 142 of the crank axle 112 contacts the retaining ring 164, oruntil there is desired amount of an axial gap between the axially facingabutment 142 of the crank axle 112 and the retaining ring 164 of thefirst crank arm 114. Next, the second end portion 132 of the crank axle112 is insert into the second axle mounting opening 170 from the secondaxially inward facing surface 116 b of the second crank arm 116 to thesecond axially outward facing surface 116 a of the second crank arm 116,preferably, until the axially facing abutment 146 contacts the axiallyinward facing surface 116 b of the second crank arm 116, or until thereis desired amount of an axial gap between the axially facing abutment146 of the crank axle 112 and the second axially inward facing surface116 b of the second crank arm 116. Finally, the fixing bolt 118 isthreaded into the crank axle 112 to secure the second end portion 132 ofthe crank axle 112 to the second crank arm 116.

Referring to FIG. 11, a bicycle crank axle assembly 210 is illustratedin accordance with a third embodiment. The bicycle crank axle assembly210 includes a crank axle 212, a first (right) crank arm 214 and asecond (left) crank arm 216. Similar to the prior embodiment, the firstand second crank arms 214 and 216 are secured to the crank axle 212using only a fixing bolt 218. The crank axle 212 includes a first endportion 230, a second end portion 232 and a middle body portion 234located between the first and second end portions 230 and 232. Thebicycle crank axle assembly 210 is identical to the bicycle crank axleassembly 10, discussed above, except that the first crank arm 214 hasbeen modified as discussed below. In view of the similarities betweenthe bicycle crank axle assembly 210 and the bicycle crank axle assembly10, only the features that are different in the bicycle crank axleassembly 210 will be discussed herein.

Here in this third embodiment, similar to the prior embodiments, thefirst end portion 230 of the crank axle 212 has a plurality of firstsplines 236, while the second end portion 232 of the crank axle 212 hasa plurality of second splines 238. The first splines 236 protruderadially outward from an outer peripheral surface 240 of the middle bodyportion 234 to define an axially facing abutment 242. The second splines238 are defined by a plurality of recesses 244 that in the second endportion 232. Each of the second splines 238 has an outermost crest thatis recessed, or almost flush with respect to the outer peripheralsurface 240 of the middle body portion 234. Thus, an axially facingabutment 246 is formed at the interface between second end portion 232and the middle body portion 234. The second end portion 232 of the crankaxle 212 has an internal thread 248 for receiving the fixing bolt 218 tosecure the second end portion 232 of the crank axle 212 to the secondcrank arm 216.

The first crank arm 214 includes a crank body portion 250, a crank axleattachment portion 252 and a plurality of sprocket attachment portions(not shown). The first crank arm 214 has a first axially outward facingsurface 214 a and a first axially inward facing surface 214 b. The crankaxle attachment portion 252 has a first axle mounting opening 260(through bore) that has a plurality of splines (identical to splines 62of FIG. 6) for engaging the first splines 236 of the crank axle 212 toprevent rotation therebetween. The first crank arm 214 is identical tothe first crank arm 14, except that the first axle mounting opening 260is larger than the first axle mounting opening 60. As a result, thecrank axle 212 is mounted in the first axle mounting opening 260 of thefirst crank arm 214 with a non-interference fit (i.e. a non-press-fit)therebetween. Accordingly, the first end portion 230 of the crank axle212 is attached to the first axle mounting opening 260 by adhesive 276.

The second crank arm 216 includes a crank axle attachment portion 266that includes a second axle mounting opening 270. The second crank arm216 has an interior space that is covered by a metallic cover member269. The second crank arm 216 has a second axially outward facingsurface 216 a and a second axially inward facing surface 216 b. Thesecond crank arm 216 is identical to the second crank arm 16. Thus,similar to the prior embodiments, the crank axle 212 is mounted thefirst and second crank arms 214 and 216 by inserting the crank axle 212through the first axle mounting opening 260 from the first axiallyoutward facing surface 214 a of the first crank arm 214 to the firstaxially inward facing surface 214 b of the first crank arm 214,preferably, until the axially facing abutment 242 of the crank axle 212contacts the axially facing abutment 264, or until there is desiredamount of an axial gap between the axially facing abutment 242 of thecrank axle 212 and the axially facing abutment 264 of the first crankarm 214. Next, the second end portion 232 of the crank axle 212 isinsert into the second axle mounting opening 270 from the second axiallyinward facing surface 216 b of the second crank arm 216 to the secondaxially outward facing surface 216 a of the second crank arm 216,preferably, until the axially facing abutment 246 contacts the secondaxially inward facing surface 216 b of the second crank arm 216, oruntil there is desired amount of an axial gap between the axially facingabutment 246 of the crank axle 212 and the second axially inward facingsurface 216 b of the second crank arm 216. Finally, the fixing bolt 218is threaded into the crank axle 212 to secure the second end portion 232of the crank axle 212 to the second crank arm 216.

Referring to FIG. 12, a bicycle crank axle assembly 310 is illustratedin accordance with a fourth embodiment. The bicycle crank axle assembly310 includes a crank axle 312, a first (right) crank arm 314 and asecond (left) crank arm 316. Similar to the prior embodiment, the firstand second crank arms 314 and 316 are secured to the crank axle 312using only a fixing bolt 318. The crank axle 312 includes a first endportion 330, a second end portion 332 and a middle body portion 334located between the first and second end portions 330 and 332. The crankaxle 312 is identical to the crank axle 12. Moreover, the bicycle crankaxle assembly 310 is identical to the bicycle crank axle assembly 110,discussed above, except that the first crank arm 314 has been modifiedas discussed below. In view of the similarities between the bicyclecrank axle assembly 310 and the bicycle crank axle assembly 110, onlythe features that are different in the bicycle crank axle assembly 310will be discussed herein.

Here in this fourth embodiment, similar to the prior embodiments, thefirst end portion 330 of the crank axle 312 has a plurality of firstsplines 236, while the second end portion 332 of the crank axle 312 hasa plurality of second splines 338. The first splines 336 protruderadially outward from an outer peripheral surface 340 of the middle bodyportion 334 to define an axially facing abutment 342. The second splines338 are defined by a plurality of recesses 344 that in the second endportion 332. Each of the second splines 338 has an outermost crest thatis recessed, or almost flush with respect to the outer peripheralsurface 340 of the middle body portion 334. Thus, an axially facingabutment 346 is formed at the interface between second end portion 332and the middle body portion 334. The second end portion 332 of the crankaxle 312 has an internal thread 348 for receiving the fixing bolt 318 tosecure the second end portion 332 of the crank axle 312 to the secondcrank arm 316.

The first crank arm 314 includes a crank body portion 350, a crank axleattachment portion 352 and a plurality of sprocket attachment portions(not shown). The first crank arm 314 has a first axially outward facingsurface 314 a and a first axially inward facing surface 314 b. The firstcrank arm 314 is identical to the first crank arm 14, except for crankaxle attachment portion 352. Here, the crank axle attachment portion 352has a first axle mounting opening 360 that is a blind bore. The firstaxle mounting opening 360 has a plurality of splines (identical tosplines 62 of FIG. 6) for engaging the first splines 336 of the crankaxle 312 to prevent rotation therebetween. However, like the thirdembodiment, the first axle mounting opening 360 is larger than the firstaxle mounting opening 60. As a result, the crank axle 312 is mounted inthe first axle mounting opening 360 of the first crank arm 314 with anon-interference fit (i.e. a non-press-fit) therebetween. Accordingly,the first end portion 330 of the crank axle 312 is attached to the firstaxle mounting opening 360 by adhesive 376. Also like the secondembodiment, the crank axle attachment portion 352 has a recess isprovided around the first axle mounting opening 360 for receiving aC-shaped retaining ring 364 for forming an axially facing abutment thatcontacts the axially facing abutment 342 of the crank axle 312.

The second crank arm 316 includes a crank axle attachment portion 366that includes a second axle mounting opening 370. The second crank arm316 has a second axially outward facing surface 316 a and a secondaxially inward facing surface 316 b. The second crank arm 316 isidentical to the second crank arm 16, except that the size of the secondaxle mounting opening 370 has been changed to accommodate the smallersize of the second end portion 332 if each of the second splines 338 hasan outermost crest that is recessed with respect to the outer peripheralsurface 340 of the middle body portion 334.

Unlike the prior embodiments, due to the first axle mounting opening 360being a blind bore, the first and second end portions 330 and 332 aredimensioned relative to the first and second axle mounting openings 360and 370 such that the first and second end portions 330 and 332 must beinserted into the first and second axle mounting openings 360 and 370from the first and second axially inward facing surfaces 314 b and 316 bof the first and second crank arms 314 and 316 toward the first andsecond axially outward facing surfaces 314 a and 316 a of first andsecond crank arms 314 and 316.

In understanding the scope of the present invention, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including”, “having” and theirderivatives. Also, the terms “part,” “section,” “portion,” “member” or“element” when used in the singular can have the dual meaning of asingle part or a plurality of parts. As used herein to describe theabove embodiment(s), the following directional terms “forward”,“rearward”, “above”, “downward”, “vertical”, “horizontal”, “below” and“transverse” as well as any other similar directional terms refer tothose directions of a bicycle equipped with the bicycle crank axleassembly. Accordingly, these terms, as utilized to describe the bicyclecrank axle assembly should be interpreted relative to a bicycle equippedwith the bicycle crank axle assembly as used in the normal ridingposition. Finally, terms of degree such as “substantially”, “about” and“approximately” as used herein mean a reasonable amount of deviation ofthe modified term such that the end result is not significantly changed.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. For example, the size, shape, location ororientation of the various components can be changed as needed and/ordesired. Components that are shown directly connected or contacting eachother can have intermediate structures disposed between them. Thefunctions of one element can be performed by two, and vice versa. Thestructures and functions of one embodiment can be adopted in anotherembodiment. It is not necessary for all advantages to be present in aparticular embodiment at the same time. Every feature which is uniquefrom the prior art, alone or in combination with other features, alsoshould be considered a separate description of further inventions by theapplicant, including the structural and/or functional concepts embodiedby such feature(s). Thus, the foregoing descriptions of the embodimentsaccording to the present invention are provided for illustration only,and not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

What is claimed is:
 1. A bicycle crank axle assembly comprising: a firstcrank arm including a first axle mounting opening that is through bore;a second crank arm including a second axle mounting opening; and a crankaxle including a first end portion, a second end portion and a middlebody portion located between the first and second end portions, thecrank axle being mounted in the first axle mounting opening of the firstcrank arm with a non-interference fit therebetween, and the first endportion of the crank axle is attached to the first axle mounting openingby adhesive, the first end portion of the crank axle having at least oneaxially extending first spline that protrudes radially outward from aradial position corresponding to an outer peripheral surface of themiddle body portion, the outer peripheral surface of the middle bodyportion and a base outer peripheral surface of the first end portionexcluding the at least one axially extending first spline having equaldiameters, the first end portion of the crank axle being disposed in thefirst axle mounting opening, the at least one axially extending firstspline non-rotatably coupling the crank axle to the first crank arm andpreventing outward axial movement of the first crank arm away from thesecond crank arm along the crank axle, the second end portion of thecrank axle having at least one recess that extend radially inward withrespect to the outer peripheral surface of the middle body portion toform at least one axially extending second spline, the second endportion of the crank axle being non-rotatably disposed in the secondaxle mounting opening.
 2. The bicycle crank axle assembly according toclaim 1, wherein the at least one axially extending first splineincludes a plurality of axially extending splines circumferentiallyspaced apart around the first end portion of the crank axle.
 3. Thebicycle crank axle assembly according to claim 1, wherein the at leastone axially extending second spline includes a plurality of axiallyextending recess circumferentially spaced apart around the second endportion of the crank axle.
 4. The bicycle crank axle assembly accordingto claim 1, wherein the second spline has an outermost crest that isrecessed with respect to the outer peripheral surface of the middle bodyportion.
 5. The bicycle crank axle assembly according to claim 1,wherein the second spline has an outermost crest that is flush withrespect to the outer peripheral surface of the middle body portion. 6.The bicycle crank axle assembly according to claim 1, wherein the firstcrank arm includes an axially facing abutment within the first axlemounting opening.
 7. The bicycle crank axle assembly according to claim6, wherein the axially facing abutment includes at least one projectionextending radially inwardly from an inner peripheral surface of thefirst axle mounting opening.
 8. The bicycle crank axle assemblyaccording to claim 6, wherein the axially facing abutment is an annularprojection extending radially inwardly from an inner peripheral surfaceof the first axle mounting opening.
 9. The bicycle crank axle assemblyaccording to claim 6, wherein the first crank arm includes a pedalattachment portion and a crank axle attachment portion defining thefirst axle mounting opening, and the axially facing abutment isintegrally formed as a unitary piece of the crank axle attachmentportion.
 10. The bicycle crank axle assembly according to claim 6,wherein the first crank arm includes a crank axle attachment portiondefining the first axle mounting opening, and the axially facingabutment is a separate piece that is attached to the crank axleattachment portion.
 11. The bicycle crank axle assembly according toclaim 10, wherein the axially facing abutment is a C-shaped retainingring that is attached to the crank axle attachment portion.
 12. Thebicycle crank axle assembly according to claim 1, wherein the first axlemounting opening of the first crank arm is defined by a first innersplined surface.
 13. The bicycle crank axle assembly according to claim1, wherein the second axle mounting opening of the second crank arm isdefined by a second inner splined surface.
 14. The bicycle crank axleassembly according to claim 1, wherein the second end portion and themiddle body portion have a maximum outer dimension that is smaller thana minimum inner dimension of the first axle mounting opening.
 15. Thebicycle crank axle assembly according to claim 1, wherein the second endportion and the middle body portion are shaped so that the second endportion and the middle body portion are capable of freely passingthrough the first axle mounting opening.
 16. The bicycle crank axleassembly according to claim 1, wherein the first and second end portionsare dimensioned relative to the first and second axle mounting openingssuch that the second end portion must be inserted into the first axlemounting opening from a first axially outward facing surface of thefirst crank arm toward a first axially inward facing surface of thefirst crank arm to dispose the first end portion in the first axlemounting opening.
 17. The bicycle crank axle assembly according to claim1, wherein the first and second end portions are dimensioned relative tothe first and second axle mounting openings such that the second endportion must be inserted into the second axle mounting opening from thesecond axially inward facing surface toward the second axially outwardfacing surface after passing through the first axle mounting opening todispose the first and second end portions in the first and second axlemounting openings, respectively.